Recently, a liquid crystal display (LCD) has been developed that has high resolution, wide viewing angle, and low power consumption. However, problems still need to be solved before the LCD replaces a cathode-ray tube (CRT). For example, in a twisted nematic (TN) LCD, moving images may appear blurred, i.e., leave a ghost or trail across the LCD at low temperature.
An electro optical panel disclosed in JP-2004-219933A includes a temperature compensation device having a temperature detection section to detect temperature of an image display area. Duration of application of a drive signal is increased in accordance with the detected temperature in order to prevent reduction in contrast ratio.
A LCD apparatus disclosed in JP-2004-177575A includes a frame frequency conversion section a temperature detection section. The frame frequency conversion section converts a frame frequency of an image signal supplied to a liquid crystal panel by interpolating sub flames into an input image frame in order to improve quality of moving images displayed on the liquid crystal panel. The temperature detection section detects temperature of the liquid crystal panel. A frame frequency conversion ratio decreases with a decrease in the detected temperature so that a liquid crystal responses within an image display period.
In a LCD apparatus disclosed in US 2005/0062712A1 corresponding to JP 2005-77946A, the number of times of repetitively outputting the same display data of one image to a liquid crystal panel is set in accordance with temperature of the liquid crystal panel in order to reduce a display frequency of the liquid crystal panel in a pseudo manner.
In a LCD apparatus disclosed in JP 2004-226470A, a display signal voltage is applied to pixels by a field reverse drive method when temperature of a liquid crystal is lower than a reference temperature and the display signal voltage is applied to the pixels by a line reverse drive method when the temperature of the liquid crystal is higher than the reference temperature.
Such a LCD apparatus is used as an in-vehicle monitor, for example, for a rear view monitor system in which a rear camera captures an image of an environment behind the vehicle and the in-vehicle monitor displays the image. When the LCD apparatus is used for the in-vehicle equipment, the blurring of the moving images becomes clearly evident due to severe temperature environment, as compared to for a household electrical appliance such as a personal computer or a television.
During the winter in cold climates, temperature in the vehicle drops down to, for example, minus 40 degree Celsius (° C.). The rear view monitor system is used, for example, when a driver backs the vehicle out of a garage, i.e., as soon as the driver enters the vehicle. Therefore, the LCD apparatus need to clearly display the moving images under the severe low temperature conditions for a few minutes until the temperature in the vehicle is raised by a heater.
In the LCD apparatus disclosed in JP-2004-219933A, JP-2004-177575A, and US 2005/0062712A1, although the field frequency changes in accordance with the temperature of the liquid crystal panel in the direct or pseudo manner, the LCD apparatus may not smoothly display the images.
In the LCD apparatus disclosed in JP-2004-226470A, the drive method switches between the field reverse drive method and the line reverse drive method in accordance with the temperature. However the polarity of the display signal voltage is always reversed per one field on each pixel. Therefore, although flickers may be reduced, the blurring may not be reduced at the low temperature.